Project Summary/Abstract Today, mothers of young children in Western societies ?look? different than they did in the past?in terms of their age, how many children they have, and whether they are married. Amidst all this change, one thing that remains the same is mothers' primary responsibility for managing their children's early health and development (Morgan & Taylor, 2006; Bianchi, 2000). The stakes of this responsibility are growing, given evidence illuminating the critical role of early childhood in lifelong health and the associated efficacy of early interventions (Heckman, 2013; Palloni, 2006). The interplay of these two trends?changes in fertility-related maternal characteristics, increased recognition of the importance of early childhood health disparities?has clear implications for children's futures. If the former are associated with how women manage their children's early health and development, then the latter means that such opportunities are crucial sources of the diverging destinies among children, especially in societies with liberal welfare regimes that enable family inequalities to be reproduced across generations. Notably, some trends (e.g., increased age at first birth, reduced fertility) are associated with greater maternal investments in children's early development while some represent potential disruptions to such investments (e.g., non-marital fertility) (Magnuson, 2007; Waldfogel, 2006; McLanahan, 2004). As these trends continue, variation around the population-level means on various maternal factors becomes more significant. For example, as women have fewer children, the potential disadvantages that a woman with several children will face navigating health care systems and securing resources to improve their children's health could increase. As another example, as more women have children without marital partners, the potential advantages that married mothers in that society enjoy promoting their children's health could diminish. If so, then how mothers compare to the new norms for mothers in their societies is meaningful for their young children's current health in ways that cascade across the life course and aggregate into population-level disparities?disparities within and across societies. The purpose of this project, therefore, is to test a life course-influenced conceptual model of the linkages among key characteristics of individual mothers, population trends in those characteristics in their home countries, their management of children's early health, and their children's physical health in six English-speaking countries (Australia, Canada, Ireland, New Zealand, United Kingdom, United States). This comparative approach is valuable because, despite some similarities, these countries vary across a variety of fertility trends and social supports. Consequently, they are diverse contexts in terms of the relative standing of different types of mothers within their societies as well as differences in the public scaffolding available in these countries to reduce the intergenerational transmission of inequality.